Copper alloy



,Patented' July 21, 1936 UNITED STATES COPPER Richards H. Harrington, signor to General Elec ration of New York ALLOY Schenectady, N. Y., astric Company, a corpo- No Drawing. Application January 31, 1935, Serial No. 4,349

5 Claims. (Cl. 148-32) The present invention relates to copper alloys and more particularly to precipitation hardened copper alloys. In Dahl Patent No. 1,847,929, March 1, 1932, there is disclosed a precipitation hardened alloy which may consist substantially of copper, beryllium and cobalt. Such an alloy is quite hard and tough and has an electrical conductivity of about 36% as compared with copper. I have found however that if a small quantity of aluminum is substituted for a portion of the beryllium in the Dahl alloy a product is obtained which has all the desired physical and chemical properties of the Dahl alloy and in addition is cheaper to fabricate, has a materially higher electrical conductivity and is characterized by a retention of its torsional elastic modulus at ele-' vated temperatures. I

In carrying out the present invention, the alloy ingredients are melted and cast in a suitable mold. The alloy forges readily in the range of 700-900 C. and if desired can be forged cold, after quenching from this range of temperature. The cast or forged material is then heated for about one to two hours at a temperature in the range of about 750 C. to about 950 C. preferably at 900 C. to effect a solid solution condition in the alloy. In general, a heating period of about two hours will be found to be sufllcient although this period of time may vary with pieces of diflerent size.

After the heat treatment to effect a solid solution, the alloy is quenched, preferably in water, and then reheated or aged at a temperature between about 400 C. and about 600 C. preferably 500 C. for a period of time which may vary from about one to four hours. This low temperature heating or aging period effects a precipitation of intermetallic compounds in the alloy and increases its hardness.

My preferred alloy composition consists of about 97% copper, 2.6% cobalt, 0.32% beryllium and 0.08% aluminum. These proportions of ingre-. dients may be varied to some extent. In any event the alloy will consist principally of copper which, in general, will comprise from about 96% to 99% of the alloy; the cobalt content may vary from about 0.5% to 3% and the combined beryllium and aluminum content may vary from about 0.25% to 1% by weight of the alloy. The beryllium and aluminum usually will be added to the other ingredients in the form of a master alloy in which the beryllium content may vary from about to 90% and the aluminum from about 50% to 10%. Preferably the master alloy will contain about 80% beryllium and about 20% aluminum.

An alloy having the preferred composition indicated above is hard, tough and resistant to corrosion. It also has an electrical conductivity 5 of about 'which is about 17% higher than the conductivity of the copper, cobalt, beryllium alloy as disclosed in the Dahl patent. In addition, the tensile properties and elastic moduli, especially the torsional elastic modulus of the alloy, 10 are maintained at useful values-from room ternperature up to about 450 C.

The present alloy has numerous applications, and may be employed to advantage as a soldering iron tip, electrical contact, pole shader, or elec- 15 trical conducting spring. Moreover owing to its desirable physical properties, it may be employed as a spring material where only strength, hardness and resistance to corrosion are of primary importance. 20

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. An alloy consisting substantially 'of copper, beryllium, aluminum and cobalt, the cobalt comprising not appreciably more than 3% of said 25 alloy, the combined beryllium and aluminum content comprising not appreciably more than 1% of the alloy, .the remainder of the alloy consisting substantially of copper.

2. An alloy consistin cobalt, beryllium and aluminum, the cobalt varying from about 0.5% to 3% of the alloy, the combined beryllium and aluminum content of the alloy varying from about 0.25% to 1%, and the remainder of the alloy consisting substantially of 35 copper.

3. An alloy consisting substantially of copper, cobalt, beryllium and aluminum, the cobalt varying from about 0.5% to 3% of the alloy, the combined beryllium and aluminum content of the 40 alloy varying from about 0.25% to 1%, the beryllium content of the alloy being at least equal to the aluminum content, the remainder of the allo consisting substantially of copper.

4. A precipitation hardened alloy consisting substantially of copper, cobalt, beryllium and aluminum, the copper content of the ,alloy varying from about 96% to 99%, the cobalt from about 0.5% to 3% and the combined beryllium and aluminum content varying from about10.25% to 1%.

5. A precipitation hardened alloy containing about 97% copper, about 2.6% cobalt, about 0.32% beryllium and about 0.08% aluminum.

RICHARDS H. HARRINGTON. 55

g substantially of copper, 30 

